Certain engines, such as Gasoline Turbocharged Direct injection (GTDI) engines, utilize high pressure fuel delivery. In such engines, firing of fuel injectors may generate fuel pressure pulsations, causing a hammering sound or “tick” noise that may be an audible disturbance to drivers, in particular at idle condition. In particular, the noise may be generated by fluidic hammering caused by the opening and closing of the injector in concert with the fuel pump pressure pulsations.
The applicant recognizes that the hammering sound may be at least partially mitigated by providing a mitigating fuel pressure pulse in the fuel rail that is substantially equal in frequency and amplitude, but opposite in polarity or phase to the fuel pressure pulse generated by firing of fuel injectors.
As such, systems and methods for modulating fuel flow of a fuel delivery system including direct injection fuel injectors of an engine to mitigate engine noise are provided. An example of such systems may include a modulating device located in the fuel delivery system upstream of the direct injection fuel injectors, the modulating device configured to generate mitigating fuel pressure pulse(s) for attenuating fuel pressure pulse(s) generated by actuation of the direct injection fuel injectors. An example of such methods may include adjusting the modulating device responsive to actuation of the direct injection injectors, wherein operation of the modulating device is varied responsive to variation of direct injection fuel injector actuation.
In such ways, engine noise caused by firing of fuel injectors in high pressure fuel delivery systems may be reduced or eliminated, making driving a more pleasant experience for drivers, even when using high pressure direct fuel injection. Specifically, in one example, pressure pulses can be generated that substantially cancel those pulses caused by the fuel injection.